H+ Vs H3O+ 兩者有何分別?

H+ may refer to free hydrogen ion at various states, for instant, solution and gaseous state.
In aqueous solution, hydrogen ion (H+) often incorporate with H2O to become hydronium ion (H3O). Yet, hydrogen ion may also occur in non-water solvent such as pure acetic acid. Therefore you may consider H+ as hydrogen ion in all medium and H3O+ as hydrogen ion exist in aqueous environment.